drop if (exporter=="PHI" | importer=="PHI")
drop if (exporter=="RUS" | importer=="RUS")
drop if (exporter=="TNT" | importer=="TNT")
drop if (exporter=="IND" | importer=="IND")
drop if (exporter=="FRA" | importer=="FRA")
drop if (exporter=="THA" | importer=="THA")
drop if (exporter=="CYP" | importer=="CYP")
drop if (exporter=="US" | importer=="US")
drop if (exporter=="VEN" | importer=="VEN")
drop if (exporter=="ELS" | importer=="ELS")
drop if (exporter=="HON" | importer=="HON")
drop if (exporter=="SUD" | importer=="SUD")
drop if (exporter=="AUST" | importer=="AUST")
drop if (exporter=="HAI" | importer=="HAI")
drop if (exporter=="SIL" | importer=="SIL")
drop if (exporter=="SKO" | importer=="SKO")
drop if (exporter=="NIG" | importer=="NIG")
drop if (exporter=="ECU" | importer=="ECU")
drop if (exporter=="PAN" | importer=="PAN")
drop if (exporter=="MEX" | importer=="MEX")
drop if (exporter=="JOR" | importer=="JOR")
drop if (exporter=="JAM" | importer=="JAM")
